<!DOCTYPE html>
<html>
    <body>
        <p>
            点击下面的按钮，循环遍历对象 "person" 的属性。
        </p>
       <button onclick="myFunction()">点击这里</button>
       <p id="demo"></p>
       <script>
       function myFunction(){
           var x;
           var txt="";
           var person={
               fname:"bill",lname:"gates",age:56
           };
           for (x in person){
               txt=txt + person[x];
           }
           document.getElementById("demo").innerHTML=txt;
       }
       </script>
    </body>
</html>